Real-time surgical reference indicium apparatus and methods for astigmatism correction

ABSTRACT

A system, method, and apparatus for guiding an astigmatism correction procedure on an eye of a patient are disclosed. An example apparatus includes a photosensor configured to record a pre-operative still image of an ocular target surgical site of the patient. The apparatus also includes a real-time, multidimensional visualization module configured to produce a real-time multidimensional visualization of the ocular target surgical site during an astigmatism correction procedure. The apparatus further includes a data processor configured to determine a virtual indicium that includes data for guiding the astigmatism correction procedure. The data processor uses the pre-operative still image to align the virtual indicium with the multidimensional visualization such that the virtual indicium is rotationally accurate. The data processor then displays the multidimensional visualization of the ocular target surgical site in conjunction with the virtual indicium.

PRIORITY CLAIM

The present application claims priority to and benefit of U.S. patentapplication Ser. No. 16/445,936 (US Pub 20190298459A1), filed Jun. 19,2019, which is a divisional of U.S. patent application Ser. No.15/234,276, filed on Aug. 11, 2016, now U.S. Pat. No. 10,368,948. TheU.S. patent application Ser. No. 15/234,276 is a continuation of, claimspriority to, and the benefit of U.S. patent application Ser. No.14/327,329, filed on Jul. 9, 2014, now U.S. Pat. No. 9,414,961, which isa divisional of, claims priority to, and the benefit of U.S. patentapplication Ser. No. 12/582,671, filed on Oct. 20, 2009, now U.S. Pat.No. 8,784,443. The entirety of each application listed above isincorporated herein by reference.

FIELD OF THE INVENTION

The present description generally relates to the field of ocularsurgery, and more particularly to ocular surgical procedures utilizingvisual imaging systems including open or unmagnified surgery andmicro-surgery, such as correction of astigmatism, utilizing visualimaging systems with magnification.

BACKGROUND

Ocular surgery, particularly when involving vision correction, is highlypatient specific, being dependent on specific features and dimensionsthat in certain cases may be significantly different from those ofexpected norms. As a result, surgeons must rely upon their individualexperience and skills to adapt whatever surgical techniques they arepracticing to the individual requirements as determined by eachpatient's unique ocular structural features and dimensions.

To date, this individualized surgical adaptation is often accomplishedessentially through freehand and best guess techniques based upon apre-surgery examination and evaluation of each individual's ocularregion and specific ocular features. This pre-surgical examination mayinclude preliminary measurements as well as the surgeon making referencemarkings directly on the patient's ocular tissues with a pen or otherform of dye or ink marking. Then, after the patient has been preparedand placed in a supine or prone position for surgery, as opposed to theoften vertical seated positioning of the patient during the pre-surgeryexaminations, the surgeon adapts the placement and configuration of theinitial surgical incisions to the actual physical dimensions andcircumstances found in the patient as the surgical procedure begins andprogresses.

Further complicating matters, ocular tissues are not conducive topre-surgery reference markings or measurements. This is particularlytrue because most ocular tissues have wet surfaces diminishing thequality of reference markings. Even further still, many ocular surgeriesinvolve internal physical structures that cannot be accessed for directmeasurement or marking prior to surgery, and therefore, the pre-surgicalmarkings on external surfaces must be visually translated onto theinternal structures actually being modified. This translation oftenleads to undesirable post-surgical outcomes.

Additionally, pre-surgical rinsing, sterilization, or drugadministration to the ocular tissues prior to or during surgery maydissolve, alter or even remove reference markings. Similarly, subsequentwiping and contact with fluids, including the patient's body fluids,during the surgical procedure may remove or distort any referencemarkings from the ocular region of interest. As a result, surgicalreference markings may lose any practical effectiveness beyond theinitial stages of the surgical procedure and in and of themselves arenot accurate as they present broad lines to indicate, in someprocedures, micro-sized incisions.

As such, there is a continuing need for effective reference indiciaproperly aligned with one or more particular ocular axis, especiallywhen proper alignment of pre-surgical data is pivotal to satisfactorypatient outcome. For instance, accurate rotational alignment ofpre-surgical data with the ocular surgery is highly advantageous whenmaking one or more limbal relaxing incisions on an eye to correct forvarying degrees of astigmatism.

Astigmatism correction is a highly sophisticated surgical procedure thatrelies on delicate incisions within or on the limbus or cornea of an eyecommonly known as limbal relaxing incisions (LRI) or astigmatickeratotomy (AK) to correct for a non-spherical topography of the eye. Inthe past, this delicate procedure has been performed based on partiallyaccurate or even inaccurate visual measurements coupled with calculatedincision templates based on those inaccurate visual measurements of apatient's eye. Past procedures have commonly relied on visualmeasurements prior to surgery and the subsequent inaccurate translationof those measurements to the limbal relaxing incision procedures wherethe positioning of the measured axis of the eye may have rotated andshifted. As a result, it is not uncommon for the placement of limbal orcorneal relaxing incisions to be improperly aligned with the naturalvertical axis of the eye, thereby resulting in residual astigmatismrequiring glasses, and can include such side effects as poor visualacuity and shadows under low ambient light conditions.

Accordingly, in spite of the ongoing development and the growingsophistication of contemporary ocular surgery, there is a continuingneed for the provision of effective reference indicia including data formaking at least one limbal or corneal relaxing incision which isrotationally accurate relative to a patient's natural vertical axis orother important axis of orientation.

SUMMARY

The apparatus and methods described herein address the long-felt needfor functional, useful, and effective ocular surgery reference markings,or indicia, including data or information for making at least one ocularrelaxing incision in an astigmatism correction surgery. The ocularrelaxing incisions described herein can be on or within the limbus orcornea of an eye, or both, for example, a limbal relaxing incision (LRI)or a corneal relaxing incision (CRI). Further, provided are apparatusand associated methods for the generation of at least one rotationallyaccurate and effective, real-time, virtual reference indicium includingdata for making at least one ocular, e.g. limbal or corneal, relaxingincision in conjunction with at least one real-time, multidimensionalvisualization of a target surgical field, or at least a portion thereof,throughout a surgical procedure or any subpart thereof. In oneembodiment, the multidimensional visualizations can be three dimensional(3D), stereoscopic, and high definition (HD). In other embodiments,portions of the imaging described herein can be performed in twodimensions.

Moreover, the virtual reference indicium, or multiple reference indicia,including data for making at least one limbal and/or corneal relaxingincision can be automated, but are placed under the direct control,adjustment, and verification of the operating surgeon or surgical team.This control enables the operating surgeon or surgical team to fine tunethe virtual reference indicia including data for making at least onelimbal and/or corneal relaxing incision as desired or needed and toalign and lock the reference indicium in place relative to theindividual patient's target ocular anatomy. Once so aligned, the virtualreference indicia including data for making at least one limbal and/orcorneal relaxing incision function as effective guides or references forthe surgeon or surgical team throughout the duration of an entireastigmatism correcting procedure or any subpart thereof.

Even further, the apparatus and methods described herein make itpossible for an operating surgeon to directly remove and reinstate atleast one real-time, virtual surgical reference indicium or indiciaincluding data for making at least one limbal and/or corneal relaxingincision as needed at any time throughout the duration of astigmatismcorrecting procedure at the control of and in response to the needs ofthe operating surgeon. An operating surgeon can also utilize multiple,different real-time, virtual reference indicia or data for making atleast one limbal and/or corneal relaxing incision sequentially orsimultaneously. Additionally, the apparatus and methods described hereinalso make it possible for the operating surgeon to replace at least oneinitial real-time, virtual reference indicium including data for makingat least one limbal and/or corneal relaxing incision with one or moresecondary or modified real-time, virtual reference indicia at anappropriate time during the surgical procedure to provide additionalsurgical guidance in real-time as desired or needed throughout theprocedure.

Exemplary apparatus and associated methods described herein accomplishthese previously unobtainable benefits through the utilization of atleast one real-time, multidimensional visualization module such as theTrueVision Systems, Inc. real-time 3D HD visualization systems asdisclosed and claimed in the Applicant's co-pending patent applicationsmade of reference herein. These exemplary multidimensional visualizationmodules function as either retrofit devices attached to existingstereomicroscopes in place of traditional microscope binocular optics oras standalone stereoscopic 3D HD visualization apparatus. Theseexemplary apparatus can include various optical or electronicmagnification systems including stereomicroscopes or can function asopen surgery apparatus utilizing overhead cameras with or withoutmagnification.

In conjunction with the multidimensional visualization module, theapparatus includes at least one data processor such as a computer ormicroprocessor with appropriate software which is configured to producein real-time, one or more virtual reference indicium including data formaking at least one limbal and/or corneal relaxing incision inconjunction with the real-time visualization of the target surgicalfield produced by the exemplary multidimensional visualization module.The data processor is provided with at least one user control inputenabling the operating surgeon, or surgical team, to adjust all, or atleast portions of the pre-operative patient data, including, forexample, a still image of an eye, to verify and lock its alignmentrelative to the multidimensional visualization of the surgical field orto suit the needs or desires of the surgeon or surgical team before orduring the surgical procedure involved.

Further, the real-time, virtual reference indicium including data formaking at least one limbal and/or corneal relaxing incision aregenerated by the at least one data processor utilizing pre-operativepatient data. Exemplary pre-operative patient data used to generate theat least one real-time virtual reference indicium including data formaking at least one limbal and/or corneal relaxing incision is generallyin the form of a pre-operative still image of an eye or, preferably anHD still image, portion of a video clip, or alternatively, an HDphotograph, all of which may be stereoscopic 3D images.

Further still, in one embodiment, the HD still image, photo orpre-operative patient data is reviewed or scanned to identify at leastone specifically identifiable or distinguishing visual feature such as ascar, vascular pattern, or physical structure found within the targetsurgical field that is static with respect to the tissues or structuresof interest in the surgical procedure. For example, the boundary of thepupil is an easily identifiable physical feature present in all eyes.Another example of a visual feature might be a dense vascular area inthe sclera, or white portion, of the eye. Such an identifiable visualfeature or combination of features is used to align and lock the HDstill image or pre-operative patient data in place with the real-timemultidimensional visualization of the target surgical field before andduring the surgical process to avoid misalignment due to naturalstructural shifts or rotations within the target surgical field.

In further accordance with the teachings of the present description, thepre-operative still image of an eye, now aligned and locked with thereal-time multidimensional visualization of the target surgical field ismodified to include at least one virtual reference indicium, includingdata for making at least one limbal relaxing incision and/or at leastone corneal relaxing incision, which is uniquely suited for anastigmatism correction procedure and the specific patient's targetanatomy. This modification is accomplished by the data processor or,alternatively, by a second dedicated data processor for generating thevirtual reference indicium or multiple reference indicia including datafor making at least one limbal and/or corneal relaxing incision, or bycombinations thereof as determined by the surgeon or surgical team. Onceincorporated into position, the at least one real-time, virtual surgicalreference indicium functions as a reference or guide to assist thesurgeon performing the relevant portion of a surgical procedure in spiteof the possibility that the target surgical field may have moved orre-oriented relative to other patient physical features or structuresafter the still image or pre-operative patient data is captured orobtained. Additionally, the included data for making at least one limbalor corneal relaxing incision can track the natural vertical axis of aneye, relative to the target surgical field. The combination of at leastone virtual reference indicium with data for making at least one limbaland/or corneal relaxing incision allows a surgeon to utilize theguidance provided by the virtual reference indicia while being alignedand locked in a position that is rotationally accurate when compared tothe natural vertical axis of an eye.

It should be noted that the real-time, virtual surgical referenceindicia and data for making at least one limbal and/or corneal relaxingincision can be presented as two dimensional (2D) or 3D indicia asappropriate or desired. For example, a virtual reference indiciumintended to direct a surgical incision of a relative flat tissue can bepresented as a 2D line incorporated into the multidimensional or 3Dvisualization provided by the visualization module. Surgeons may prefer3D indicium or natural patient vertical when operating on more complexshapes and surfaces.

The surgeon is able to utilize the reference indicium including data formaking at least one limbal and/or corneal relaxing incision as a patternor guide which is aligned and rotationally accurate and locked into theeye's natural vertical axis. In order to make the proper limbal orcorneal relaxing incisions, the virtual indicium is accuratelydimensioned and rotationally aligned with the eye's natural verticalaxis and visual features of the eye, and incorporated into the 3D HDvisualization, rather than being marked directly onto the exterior ofthe patient's eye as in the prior art where it would at best be anapproximation of the incision locations.

Further advantages and features of the apparatus and methods describedherein will be provided to those skilled in the art from a considerationof the following Detailed Description taken in conjunction with theassociated Figures, which will first be described briefly.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an illustration of an exemplary image capture module of thepresent description.

FIG. 2 is an illustration of an exemplary apparatus of the presentdescription retrofitted on a surgical microscope.

FIG. 3 is a schematic overview of an exemplary embodiment of anapparatus of the present description illustrating features thereof.

FIG. 4 is a plan view of an exemplary alignment control panel of thepresent description illustrating an exemplary embodiment of user inputcontrol thereof.

FIG. 5A is a cross-section of a human eye illustrating its structuralelements and features.

FIG. 5B is an angled perspective view of a human eye illustrating itsstructural elements and features.

FIG. 6A is a front view of a human eye with a chemically dilated pupilillustrating the optical axis of the eye.

FIG. 6B is a front view of a human eye with a naturally dilated pupilillustrating the line of sight or the visual axis of the eye.

FIG. 6C is a front view of a human eye illustrating naturalcyclorotation.

FIG. 7 is a front view of a human eye of a patient illustrating anexemplary embodiment of a real-time 3D HD visualization overlaid with analigned HD pre-operative patient data still image of the patient eye.

FIG. 8 is a chemically dilated eye with a generated indicium includingdata for making two limbal relaxing incisions and other alignmentfeatures.

FIG. 9 is a chemically dilated eye with another alternate indiciumincluding data for making four limbal relaxing incisions and otheralignment features.

FIG. 10 is a chemically dilated eye with another indicium including datafor making two sets of limbal relaxing incisions and other alignmentfeatures.

FIG. 11 is a chemically dilated eye with an indicium including data formaking limbal relaxing incisions and a corneal relaxing incision in theform of spots and other alignment features.

FIG. 12 is a chemically dilated eye with another indicium including datafor making limbal and corneal relaxing incisions.

DETAILED DESCRIPTION

Described herein are apparatus and methods for generating one or morerotationally accurate, real-time, virtual reference indicium, ormultiple indicia, including data for making at least one ocular relaxingincision in conjunction with at least one real-time, multidimensionalvisualization of at least a portion of a target surgical fieldthroughout a surgical procedure or any subpart thereof. The ocularrelaxing incisions described herein can be on or within the limbus orcornea of an eye, or both, for example, a limbal relaxing incision (LRI)or a corneal relaxing incision (CRI), also known as astigmatickeratotomy (AK). In some embodiments, at least one element of theimaging described herein is stereoscopic. In one embodiment, themultidimensional visualization is stereoscopic three-dimensional (3D)video and also may be in high definition (HD). Those skilled in the artwill appreciate that a 3D HD real-time visualization will be mosteffective in enabling a physician to perform an astigmatism correctingprocedure. However, two dimensional (2D) systems or portions thereof canbe useful according to the present description.

Moreover, the virtual reference indicia including data for making atleast one limbal and/or corneal relaxing incision can be placed underthe direct control and adjustment of the operating surgeon or surgicalteam, thereby enabling the surgeon to have tight control over thereference indicia and properly align it to an eye's natural verticalaxis. Once the surgeon has aligned the virtual reference indiciaincluding data for making at least one limbal and/or corneal relaxingincision, it can be locked in place and act as an effective guide forthe surgeon throughout any or all portions of a surgical procedure atthe discretion and control of the surgeon or surgical tem.

“Rotationally accurate” as used herein refers to a systems ability toproperly track an eye's natural vertical axis (also referred to as apatient's ocular natural vertical axis). As such, the at least onevirtual reference indicia including data for making at least one limbaland/or corneal relaxing incision described herein is rotated accuratelyrelative to the eye's natural vertical axis. Accuracy of the systems andmethods described herein for rotationally tracking the natural verticalaxis is within less than about 1 degree in other embodiments, theaccuracy can be within less than about a half a degree or a quarter of adegree. The virtual reference indicia can also include information aboutthe eye's natural vertical axis in addition to accurately tracking it.Virtual reference indicia including data for making at least one limbaland/or corneal relaxing incision are further described in theembodiments of the present description.

As an added benefit, the real-time virtual reference indicia includingdata for making at least one limbal and/or corneal relaxing incision canbe positioned accurately at the appropriate depth within the targetsurgical field to precisely indicate the correct reference indiciumsize, shape, and position on the tissue or tissues of interest as wellas accurately align the surgical procedure with the natural verticalaxis of the eye. Further, varying real-time virtual reference indiciaincluding data for making at least one limbal and/or corneal relaxingincision can be generated within the real-time multidimensionalvisualization as appropriate during different phases of the surgicalprocedure where different ocular tissues or structures are subsequentlytargeted or exposed, or to track moving ocular tissues or structures inreal-time and to realign the real-time virtual reference indicia asappropriate. Additionally, the color, luminosity, transparency, or othervisual characteristics of the virtual reference indicia and data formaking at least one limbal and/or corneal relaxing incision may bealtered by a surgeon or at least one data processor as appropriate toenhance their contrast and visibility relative to the colors andtextures of the actual target surgical site to assist the surgeon inperforming the surgical procedure.

In a broad aspect, illustrating these beneficial features, an exemplaryapparatus incorporates three primary elements: at least one real-timemultidimensional visualization module, at least one data processor, andat least one user control input. The three elements can be physicallycombined into a single device or can be linked as physically separateelements within the scope and teachings of the present disclosure asrequired by the specific surgical procedure being practiced.

An exemplary real-time multidimensional visualization module suitablefor practicing the present methods incorporates the basic structuralcomponents of the Applicant's TrueVision Systems, Inc. real-time 3D HDvisualization systems described in the Applicant's co-pending U.S.application Ser. No. 11/256,497 entitled “Stereoscopic Image AcquisitionDevice,” filed Oct. 21, 2005; Ser. No. 11/668,400 entitled “StereoscopicElectronic Microscope Workstation,” filed Jan. 29, 2007; Ser. No.11/668,420 entitled “Stereoscopic Electronic Microscope Workstation,”filed Jan. 29, 2007; Ser. No. 11/739,042 entitled “Stereoscopic DisplayCart and System,” filed Apr. 23, 2007; and Ser. No. 12/417,115, entitled“Apparatus and Methods for Performing Enhanced Visually DirectedProcedures Under Low Ambient Light Conditions,” filed Apr. 2, 2009, allof which are fully incorporated herein by reference as if part of thisspecification.

The multidimensional visualization module is used to provide a surgeonwith a real-time visualization of at least a portion of a targetsurgical field, which in the present application is an eye.

“Real-time” as used herein generally refers to the updating ofinformation at essentially the same rate as the data is received. Morespecifically, “real-time” is intended to mean that the image data isacquired, processed, and transmitted from the photosensor of thevisualization module at a high enough data rate and at a low enough timedelay that when the data is displayed, objects presented in thevisualization move smoothly without user-noticeable judder, latency orlag. Typically, this occurs when the processing of the video signal hasno more than about 1/10^(th) second of delay.

It should be appreciated that while it is preferred to utilize amultidimensional visualization module that provides a surgeon with areal-time 3D visualization of at least a portion of the target surgicalfield, it is contemplated as being within the scope of the presentdisclosure for the visualization module to provide a real-timevisualization that is a real-time 2D visualization. However, the use ofa 3D visualization is preferred as it provides many benefits to thesurgeon including more effective visualization and depth of fieldparticularly with regard to the topography of an eye. In one embodiment,the visualization of the target surgical field is in high definition(HD).

The term “high definition” or “HD” as used herein can encompass a videosignal having a resolution of at least 960 lines by 720 lines and togenerally have a higher resolution than a standard definition (SD)video. For purposes of the present invention, this can be accomplishedwith display resolutions of 1280 lines by 720 lines (720p and 720i) or1920 lines by 1080 lines (1080p or 1080i). In contrast, standarddefinition (SD) video typically has a resolution of 640 lines by 480lines (480i or 480p) or less. It is however, within the scope of thepresent description that the multidimensional visualization can be inSD, though HD is preferred.

The apparatuses described herein can be embodied in a single devicewhich can be retrofitted onto existing surgical equipment such assurgical microscopes or open surgery apparatus. This is highlyadvantageous as retrofit embodiments can be added to existing systems,allowing expensive equipment to simply be upgraded as opposed topurchasing an entirely new system. The exemplary apparatus can includevarious optical or electronic magnification systems includingstereomicroscopes or can function as open surgery apparatus utilizingcameras and overhead visualizations with or without magnification.

FIG. 1 illustrates image capture module 100 which includes amultidimensional visualization module and an image processing unit, bothhoused within image capture module 100, and therefore, not depicted. Theexemplary image capture module comprises at least one photosensor tocapture still images, photographs or videos. As those skilled in the artwill appreciate, a photosensor is an electromagnetic device thatresponds to light and produces or converts light energy into anelectrical signal which can be transmitted to a receiver for signalprocessing or other operations and ultimately read by an instrument oran observer. Communication with image capture module 100 includingcontrol thereof and display output from image capture module 100 areprovided by first connector 102. Image capture module power is providedby second connector 104. Additionally, image capture module 100 canmanually control the transmitted light intensity using iris sliderswitch 106.

In another embodiment, FIG. 2 illustrates retrofitted surgicalmicroscope 200 incorporating image capture module 100 retrofittedthereto. Retrofitted surgical microscope 200 includes image capturemodule 100 coupled to first ocular port 202 on ocular bridge 204.Further, ocular bridge 204 couples video camera 206 to a second ocularport (not shown) and binocular eyepiece 208 to third ocular port 210.Optional forth ocular port 212 is available for further additions toretrofitted surgical microscope 200. Although retrofitted surgicalmicroscope 200 includes image capture module 100, it still retains theuse of conventional controls and features such as, but not limited to,iris adjustment knob 214, first adjustment knob 216, second adjustmentknob 218, illumination control knob 220, and an objective lens (notshown) Further still, image capture module 100 can send and receiveinformation through signal cable 222 which is connected to firstconnector 102, while power is supplied via second connector 104 of imagecapture module 100.

An exemplary, non-limiting configuration of components is illustrated inFIG. 3 . Apparatus setup 300 includes image capture module 100, coupledto photosensor 304 by bi-directional link 306. Those skilled in the artwill appreciate that bi-directional link 306 can be eliminated whereimage capture module 100 and photosensor 304 are physically the samedevice. Image capture module 100 is in direct communication with imageprocessing unit 308 by first cable 310. First cable 310 can be a cableconnecting to physically different devices, can be a cable connectingtwo physically different components within the same device, or can beeliminated if image capture module 100 and image processing unit 308 arephysically the same device. First cable 310 allows, in certainembodiments, bi-directional communication between image capture module100 and image processing unit 308. Image processing unit 308 generatesimages and videos that are displayable on display 312. It is within thescope of the present description that display 312 include multipledisplays or display systems (e.g. projection displays). An electricalsignal (e.g. video signal) is transmitted from image processing unit 308to display 312 by a second cable 314, which is any kind of electricalsignal cable commonly known in the art. Image processing unit 308 can bein direct communication with multidimensional visualization module 316,which can also send electrical signals to display 312 via second cable314. In one embodiment, image capture module 100, image processing unit308, and multidimensional visualization module 316 are all housed in asingle device or are physically one single device. Further, one or allof the components of the present invention can be manipulated by controlpanel 318 via cable network 320. In one embodiment, control panel 318 iswireless.

“Display,” as used herein, can refer to any device capable of displayinga still or video image. Preferably, the displays of the presentdisclosure display HD still images and video images or videos whichprovide a surgeon with a greater level of detail than a SD signal. Morepreferably, the displays display such HD stills and images instereoscopic 3D. Exemplary displays include HD monitors, cathode raytubes, projection screens, liquid crystal displays, organic lightemitting diode displays, plasma display panels, light emitting diodes,3D equivalents thereof and the like. In some embodiments, 3D HDholographic display systems are considered to be within the scope of thepresent disclosure. In one embodiment, display 312 is a projection cartdisplay system and incorporates the basic structural components of theApplicant's TrueVision Systems, Inc. stereoscopic image display cartdescribed in the Applicant's co-pending U.S. application: Ser. No.11/739,042. In another embodiment, display 312 is a high definitionmonitor, such as one or more liquid crystal displays (LCD) or plasmamonitors, depicting a 3D HD picture or multiple 3D HD pictures.

The exemplary image processing units as illustrated in FIGS. 1, 2, and 3include a microprocessor or computer configured to process data sent aselectrical signals from image capture module 100 and to send theresulting processed information to display 312, which can include one ormore visual displays for observation by a physician, surgeon or asurgical team. Image processing unit 308 may include control panel 318having user operated controls that allow a surgeon to adjust thecharacteristics of the data from image capture module 100 such as thecolor, luminosity, contrast, brightness, or the like sent to thedisplay.

In one embodiment, image capture module 100 includes a photosensor, suchas a camera, capable of capturing a still image or video images,preferably in 3D and HD. However, the photosensor can also capture stillimages or video in 2D. It is within the teachings herein that thephotosensor is capable of responding to any or all of the wavelengths oflight that form the electromagnetic spectrum. Alternatively, thephotosensor may be sensitive to a more restricted range of wavelengthsincluding at least one wavelength of light outside of the wavelengths ofvisible light. “Visible light.” as used herein, refers to light havingwavelengths corresponding to the visible spectrum, which is that portionof the electromagnetic spectrum where the light has a wavelength rangingfrom about 380 nanometers (nm) to about 750 nm.

More specifically, the at least one data processor is also in directcommunication with multidimensional visualization module 316 and/orimage capture module 100. The data processors, in their basic form, areconfigured to produce at least one real-time virtual reference indiciumincluding data for making at least one limbal and/or corneal relaxingincision in conjunction with the real-time visualization of at least aportion of the target surgical field produced by multidimensionalvisualization module 316. In one embodiment, the data processor orprocessors are incorporated into multidimensional visualization module316. In another embodiment, at least one data processor is a stand aloneprocessor such as a workstation, personal data assistant or the like.

The at least one data processor is controlled by built-in firmwareupgradeable software and at least one user control input, which is indirect communication with the data processors. The at least one usercontrol input can be in the form of a keyboard, mouse, joystick, touchscreen device, remote control, voice activated device, voice commanddevice, or the like and allows the surgeon to have direct control overthe one or more virtual surgical reference indicium.

FIG. 4 illustrates an exemplary user control input, in the form ofcontrol panel 318. Control panel 318 includes multidirectionalnavigation pad 402 with user inputs allowing a controlling surgeon oroperator to move data vertically, horizontally or any combination of thetwo. Additionally, the depth of the data can be adjusted using depthrocker 404 of control panel 318 and the rotation can be adjusted usingrotation rocker 406 of control panel 318. Depth can be adjusted usingboth increase depth position 408 and decrease depth position 410 ofdepth rocker 404. Additionally, rotation can be adjusted using bothincrease rotation position 412 and decrease rotation position 414 ofrotation rocker 406. Other non-limiting adjustments that can be made tothe pre-operative image or to the real-time visualization includechanges in diameter, opacity, color, horizontal and vertical size, andthe like, as known in the art. It should be noted that in exemplarycontrol panel 318 an adjustment can be undone by the surgeon utilizing“back” button 416. Further, the entire process can be ended by thesurgeon by engaging “cancel” button 418. Further, once the surgeon issatisfied with the alignment of the data, the alignment is locked intoplace by engaging “ok” button 420.

Alternative control panel embodiments for the manipulation and alignmentof the pre-operative still image are contemplated as being within thescope and teachings of the present description. For example, a hand-helddevice such as a 3D mouse can be used as known in the art to directlyposition templates, images, and references within the real-timemultidimensional visualization. Such devices can be placed on a tabletopor held in mid-air while operating. In another embodiment, foot switchesor levers are used for these and similar purposes. Such alternativecontrol devices allow a surgeon to manipulate the pre-operative stillimage without taking his or her eyes off of the visualization of asurgical procedure, enhancing performance and safety.

In yet another alternative embodiment, a voice activated control systemis used in place of, or in conjunction with, control panel 318. Voiceactivation allows a surgeon to control the modification and alignment ofthe pre-operative still image and its associated indicia as if he wastalking to an assistant or a member of the surgical team. As thoseskilled in the art will appreciate, voice activated controls typicallyrequire a microphone and, optionally, a second data processor orsoftware to interpret the oral voice commands. In yet a furtheralternative embodiment, a system is envisioned wherein the apparatusutilizes gesture commands to control pre-operative image adjustments.Typically, as known in the art, the use of gesture commands involves anapparatus (not shown) having a camera to monitor and track the gesturesof the controlling physician and, optionally, a second data processor orsoftware to interpret the commands.

In one embodiment, apparatus setup 300 can be used in many medicalsettings. For example, apparatus setup 300 can be used in an examinationroom. Therein, image capture module 102 utilizes photosensor 304 tocapture pre-operative patient data such as still images, preferably inHD, and information relating to a patient's natural vertical axis.Photosensor 304 can be coupled to any piece of medical equipment that isused in an examination room setting wherein pre-operative data can becaptured. Image capture module 100 directs this data to image processingunit 308. Image processing unit 308 processes the data received fromimage capture module 100 and presents it on display 312.

In another embodiment, apparatus setup 300 can be used in an operatingroom. Therein, image capture module 100 utilizes photosensor 304 tocapture a real-time visualization of at least a portion of the targetsurgical field, preferably in HID, more preferably in 3D. However, a 2Dreal-time visualization of at least a portion of the target surgicalfield is also possible. Image capture module 100 directs this data toimage processing unit 308 including multidimensional visualizationmodule 316. Image processing unit 308 including multidimensionalvisualization module 316 processes the data received from image capturemodule 100 and presents it on display 312 in real-time.

In one exemplary embodiment, apparatus setup 300 is used in an operatingroom and photosensor 304 is a surgical microscope. Therein, imagecapture module 100 is retrofitted on the surgical microscope. The use ofa surgical microscope in combination with apparatus setup 300 allows asurgeon to comfortably visualize a surgical procedure on one or moredisplays instead of staring for, in some cases, several hours though theeyepiece of a surgical microscope.

Apparatus setup 300 used in an examination room can be in directcommunication with apparatus setup 300 used in the operating room. Thetwo apparatus setups can be directly connected by cable, or indirectlyconnected through an intermediary device such as a computer server. Insome embodiments, the two sections can be separate systems, even indifferent physical locations. Data can be transferred between the twosystems by any means known to those skilled in the art such as anoptical disc, a flash memory device, a solid state disk drive, a wirednetwork connection, a wireless network connection or the like.

A further understanding of the present disclosure will be provided tothose skilled in the art from an analysis of exemplary steps utilizingthe apparatus described above to practice the associated methodsdisclosed herein.

Though the apparatus and associated methods are applicable to any typeof surgery on any target structure or tissue, the exemplary features andadvantages will be disclosed in the illustrative, but non-limitingcontext of ocular surgery, particularly astigmatism correctionprocedures using at least one limbal and/or corneal relaxing incision.This type of surgical procedure is quite common as astigmatism ispresent in about 65% of patients at levels of 0.5 diopter or more.Further, it is not uncommon for this type of procedure to accompany acataract surgery wherein an intraocular lens (IOL) is implanted. Forreference, there are over three million IOL implantation procedures doneper year in the United States and astigmatism correction oftenaccompanies this procedure.

The apparatus and methods described herein are useful as a standaloneprocedure to correct small to medium levels of astigmatism (generallybelow about 3 diopters, but can be used to correct up to 8 diopters).The apparatus and methods described herein are also specificallyadaptable for use in addition to IOL implantation without modification.The apparatus and methods described herein can be used to guide asurgeon in making one or more limbal relaxing incisions and/or one ormore corneal relaxing incisions.

Referring to FIG. 5A, a cross-sectional view of a general structure ofeye 500 is provided. In FIG. 5B, an angled perspective view of eye 500is provided Eye 500 contains natural crystalline lens 502 encased inanterior capsule 504 and posterior capsule 506. Eye 500 also includescornea 508, the circumference of which is defined by limbus 510, whichis the border between cornea 508 and the sclera 512. As light enters theeye through cornea 508, it passes through iris 514 and is focused bynatural crystalline lens 502 at a focal point on retina 516.

Astigmatism occurs, in part, when cornea 508 and natural crystallinelens 502 do not properly focus light onto retina 516 at a focal point.Astigmatism is a vector with two components, vertical astigmatism andhorizontal astigmatism. For example, a patient can have adequate focusin the horizontal plane, but have several diopters of astigmatism in thevertical plane. The opposite can also be true. However, in practice, itis generally a mix of astigmatism in the two planes that presents, andthus, astigmatism is defined along an axis or meridian between 0 and 180degrees.

Differences in astigmatism generally result from imperfections in thecurvature of cornea 508. In the last 20 years, advancements in ocularsurgery have allowed the use of a rather non-invasive procedure tocorrect for small to moderate amounts of astigmatism. Initially, it wasdiscovered that small incisions to cornea 508 could effectively resultin reduction or in some cases complete elimination of astigmatism byeffectively changing the curvature of cornea 508 thereby allowing lightto properly be focused on retina 516. These incisions became known ascorneal relaxing incisions. However, it was discovered that patients whounderwent such procedures could develop side effects such as artifacts,haloes and problems with night vision. Despite the drawbacks of cornealrelaxing incisions, they are still readily used by surgeons to correctfor astigmatism.

As a result of the drawbacks and side effects of corneal relaxingincisions, procedures were developed wherein small incisions to limbus510 at calculated positions could reduce or eliminate small to mediumdegrees of astigmatism without the side effects of corneal relaxingincisions. Cutting positions on the limbus allow the corneal tissue torelax and in effect changes the curvature of the cornea. Theseprocedures have been named limbal relaxing incisions and have shown muchpromise in the field of ocular surgery as a result of their low degreeof side effects and the relatively non-invasive nature of theprocedures.

However, despite the success of limbal relaxing incision procedures, itis not uncommon for the procedure to be a trial and error procedure fora surgeon. Measured astigmatism data is commonly translated to incisioncutting data using approximation formulas that have been developed overtime and published for reference. Then, after incision cutting data hasbeen generated, commonly in a pattern of one or more incision arcs to becut, the surgeon either free hand cuts the incisions using best guess orstamps approximate arcs on the sclera to be incised using anyappropriate marking tool known in the art.

Further, complicating matters and contributing to the possibility ofless than optimal patient outcomes is a natural phenomenon of the humaneye known as cyclorotation or cyclotorsion. Cyclorotation refers to thecondition where, when a patient lays down from a generally verticalorientation into a supine or generally horizontal position, thepatient's eyes rotate away from the measured vertical axis by a variableamount which ranges from about −12 to about +12 degrees. Because limbalrelaxing incisions and corneal relaxing incisions need to be lined upwith the vertical axis of an eye, it is important that the astigmatismdata and resulting incision cutting data track the vertical axis of theeye.

With this understanding of the contemporary need for accurately andprecisely placed, and rotationally accurate limbal relaxing incisionsand corneal relaxing incisions, the following non-limiting, exemplaryembodiments illustrate the previously unobtainable features andadvantages of the apparatus and methods with relation to providing atleast one accurate, real-time virtual reference indicium including datafor making at least one limbal and/or corneal relaxing incision that canguide a surgeon in performing a properly and rotationally accuraterelaxing incision or multiple incisions.

As a first step in an astigmatism correcting procedure according to thepresent description, a pre-operative data set is captured or obtained.The pre-operative data set can include any portion of data about apatient including, for example, the patient's weight, age, hair color,bodily features, medical history, and at least one image of at least aportion of the patient's target surgical anatomy, specifically the eye,information about axes of the eye of the patient, astigmatism dataincluding steep k and flat k, and the like. According to one embodiment,the pre-operative data set includes the vertical axis of the patient'seye. The vertical axis as used herein is a measurement based at leastpartially on natural line of sight incorporating the patient's naturalvisual axis relative to changes in orientation of the target surgicalfield or the visual axis itself. A patient's natural vertical axis isindicated in chemically dilated eye 600 of FIG. 6A by vertical axisidentifier 602.

In an exemplary embodiment, the pre-operative dataset, or pre-operativepatient data includes a still image of at least a portion of the eye ofthe patient undergoing an astigmatism correcting procedure along with ameasurement of the vertical axis of the patient's eye as well as datasuch as steep k and flat k. In some embodiments, the pre-operative stillimage is in HD. A pre-operative data set can also include a mark-up ofthe patient's eye for analysis, measurement, or alignment as well astopographical data or measurements.

It will be appreciated by those skilled in the art that the opticalaxis, and the visual axis of an eye are not necessarily synonymous oridentical in fact they vary depending upon ambient light conditions andmay diverge from one another depending on the nature of pupil dilation.“Dilation” of an eye is a retraction of the iris, opening the pupil ofthe eye and allowing more light to reach the retina. In most surgeryconducted under bright lighting, pupil dilation is commonly accomplishedusing chemical dilating agents to relax the iris sphincter musclethereby increasing the circumference of the iris to a maximal extent. Inthis manner the surgeon is provided with a clear view and subsequentaccess to internal structures of the eye.

However, chemically induced pupil dilation produces a markedly differentshaped pupil and pupillary boundary as well as a different pupillarycenter point location from that produced by natural dilation. Forexample, as illustrated in FIG. 6A (reference is also made to FIG. 5A),chemically dilated eye 600 has dilated iris 604 that produces a large,generally symmetrical pupil 606 concentric with the observed opticalaxis center point 608. This corneal center reference point is very closeto that defined by the geometric center of the circle formed by theintersection of the patient's limbus 510. As depicted in FIG. 5A,optical axis 520 is defined by a line connecting the anterior pole, oroptical axis center point 608, and the posterior poles, or retinalcenter point 522, of the eye. Further, the vertical axis of an eye isgenerally in an upright configuration as indicated by vertical axisidentifier 602. As will be discussed, this vertical axis can shift, orreorient, depending on the patient's orientation.

In contrast to symmetrical chemical dilation, naturally dilated eye 630,as shown in FIG. 6B, generally presents itself in low ambient light orno light conditions where natural dilated iris 632 naturally retracts toa lesser extent than under chemical dilation. More importantly,naturally dilated eye 630 is not symmetrical and produces asymmetricalpupil 634 that is generally biased nasally (towards the nose) andsuperiorly (up from center) as indicated by arrow 636 relative tosymmetrical pupil 606 shown in FIG. 6A and is generally unique for eachpatient. As a result of this asymmetrical dilation, the patient'snatural line of sight center point 638 as defined in the patient'scornea by the center of asymmetrical pupil 634 is also biased away fromobserved optical axis center point 608 observed under chemical dilationin FIG. 6A Therefore, under non-chemical dilation conditions, apatient's optical and visual axis corneal center points may not, andtypically do not, line up.

This difference between an observed optical axis center point 608 andnatural line of sight center point 638 is further illustrated by thecross-sectional view of eye 500 illustrated in FIG. 5A. There, thechemically-induced observed optical axis center point 608 is illustratedas being generally centrally disposed at the center of cornea 508 asdefined by the chemically induced symmetrical pupil 606. In contrast,natural line of sight center point 638 is shown at a position that isgenerally nasally and superiorly biased away from observed optical axiscenter point 608 near the center of cornea 508 as defined by naturalasymmetrical pupil 634. The resulting visual axis 524 passes throughnatural line of sight center point 638 and terminates at focal point 526of eye 500. As those skilled in the art will appreciate, surgicalprocedures designed to improve or restore a patient's vision will bemore effective if the procedures are based upon the patient's true ornatural line of sight center point 638 as opposed to chemically inducedobserved optical axis center point 608 that has a lesser relation to howthe patient's eye naturally focuses light to the high resolution focalpoint of the patient's retina at the fovea, or focal point 526. As willbe discussed, the vertical axis identifier 602 can shift depending onthe patient's orientation.

FIG. 6C illustrates this phenomenon of cyclorotation as eye 660 rotatesaway from the normal or originally measured vertical axis 662 byvariable angle 664 when a patient assumes a prone or supine position.This rotation is further illustrated by the shifting of observable orvisual scleral features 666 and 668 which also have rotated by variableangle 664. Thus, originally measured vertical axis 662 of the patient'seye, generally taken with the patient sitting in a vertical orientation,and any associated physical or structural aberrations and the resultantspherical distortions or astigmatism measured relative thereto, candiffer from those of observed vertical axis 670, of the eye when thepatient lays down into a supine or generally horizontal position, wheremost ocular surgeries take place, and the target eye cyclorotates intothis displaced orientation. The present apparatus and methods make itpossible for the surgeon to maintain the proper orientation, orrotational accuracy, of limbal relaxing incisions relative to thepatient's originally measured vertical axis 662 by providingrotationally accurate reference indicia including data for making atleast one limbal relaxing incision, which are aligned with observedvertical axis 670.

Prior to the presently disclosed apparatus and methods, it was theindividual and variable skill of the surgeon at compensating for thesenatural physical differences between measured optical and vertical axisduring the surgical procedure that determined the degree ofpost-operative success of the procedures involved in the ocular surgeryand the resultant degree of patient satisfaction with the procedure.

The apparatus and methods of the present description provides a surgeonwith the ability to create and use one or more user adjustable,accurate, real-time, virtual reference indicium including data formaking at least one limbal and/or corneal relaxing incision whichclearly and accurately take into account the natural vertical axis ofthe patient despite any shifting due to cyclorotation or asymmetricaldilation resulting from changes in the patient's physical positioningbetween pre-operative examination and surgery.

In one embodiment, wherein a pre-operative data set is collected, inorder to properly measure the vertical axis of the eye, astigmatism dataand other pre-operative data, a slit lamp microscope is used to collectthe data. A “slit lamp” is an instrument commonly consisting of a highintensity light source that can be adapted to focus and shine the lightas a slit A slit lamp allows an optometrist or ocular surgeon to viewparts of the eye in greater detail than can be attained by the nakedeye. Thus, a slit lamp can be used to view the cornea, retina, iris andsclera of a patient's eye or to identify the vertical, optical or visualaxis of a patient's eye. A conventional slit lamp can be retro-fittedwith an image capture module as described herein, preferably with atleast one photosensor. This allows a surgeon or optometrist tocomfortably collect accurate and reliable pre-operative patient dataincluding at least one still image of the patient's eye, preferablyunder natural dilation and most preferably in HD.

In one embodiment, this is accomplished under natural dilation or withan un-dilated iris to clearly view and examine the patient's eye. Thiscan also be accomplished in low ambient light because the exemplaryvisualization modules described herein are able to produce an accurate3D HD image in at least one wavelength outside of the wavelengths ofvisible light. As an added benefit, collecting the pre-operative patientdata under low ambient light conditions accurately identifies thevertical axis of the patient's eye for subsequent tracking and referencewithout sacrificing visual acuity for the physician.

In a second step, the pre-operative data set still image, or just stillimage, captured in the first step is matched to a real-timemultidimensional visualization of at least a portion of the targetsurgical field. Matching the still image to the multidimensionalvisualization is important because the target surgical field may havechanged since the pre-operative image still was captured such as bytissue shifting and rotating when the patient changes position. As aresult, the measurements obtained during the pre-operative examinationmay no longer be accurate or easily aligned in light of such changes inthe patient's physical alignment and position. Additionally, anysurgical markings that may have been applied to the patient's tissuesduring the pre-operative examination may have shifted, been wiped away,or blurred.

At this point, the pre-operative still image of the patient's eye isanalyzed by a surgeon, a surgical team or the at least one dataprocessor of the apparatus to identify at least one distinct visiblefeature that is static and recognizable relative to and within the stillimage of the eye. Utilizing the teachings described herein, this atleast one distinct visible feature is used to align the image with thereal-time multidimensional visualization of the target surgical fieldduring the actual surgery. Preferably, this real-time visualization is a3D HD visualization of the target surgical field.

For example, referring to FIG. 6A, one or more exemplary distinctvisible features that can be identified are illustrated in sclera 610 ofeye 600. However, recognizable visible features can also be identifiedwithin the iris, on the cornea, or on the retina of the eye. Exemplarydistinct visible features include, without limitation, surfacevasculature 612, visible vascular networks 614 and vascular branchingpatterns 616, iris patterns 618, scratches on the cornea, dimples on thecornea, retinal features 620, deformities, voids, blotches, sequesteredpigment cells, scars, darker regions, and combinations thereof.Additionally, both the pupillary boundary and limbus are distinctvisible features, either of which can be utilized in accordance with theteachings of the present description to align and track the image inconjunction with the real-time visualization of the target surgicalfield.

In one embodiment, once at least one distinct visible feature has beenidentified in the pre-operative patient data still image, the stillimage and the associated visible feature or features are stored forlater processing and use in the operating room. It should be noted thatthe pre-operative patient data need not be taken in a separate operationor at a separate location from the operating room or theater. Forexample, during surgery to repair a traumatic injury or to simplify apatients visit, the entire process can be performed in the operatingroom to save time.

A third step involves the surgeon, the surgical team, the at least onedata processor, or a combination thereof aligning the pre-operativestill image of the target surgical field with the real-timemultidimensional visualization of the target surgical field. Generallyspeaking, this alignment is accomplished utilizing specific staticvisual features identified within the pre-operative still image of thetarget surgical site to align the still image with the real-timemultidimensional visualization of the target surgical field. This allowsthe pre-operative image to be aligned accurately with the tissues of thetarget surgical field regardless of whether the target surgical fieldhas shifted, rotated or reoriented relative to other patient tissues orstructures following collection of the pre-operative data.

The pre-operative still image of the patient's eye is overlaid on one ormore real-time 3D HD visualizations of at least a portion of thepatient's target surgical field for at least a portion of the surgicalprocedure. Referring to FIG. 7 , exemplary real-time 3D HD visualization700 of a patient's eye is overlaid with pre-operative patient data stillimage 702 of the same eye. Previously identified and recognizabledistinct vascular networks in the sclera of the patient's eye,identified on the left as reference numeral 704 and on the right asreference numeral 706 of eye 708 are used to align pre-operative patientdata still image 702 with real-time 3D HD visualization 700.

It should be noted that pre-operative patient data still image 702 isshown as being rotated relative to real-time 3D HD visualization 700,for example by a surgeon, to account for the naturally occurringcyclorotation of the patient's target eye as a result of the patientlying down for surgery. The previously identified distinct visualfeatures 704 and 706 are used to rotate and align patient data stillimage 702 with the corresponding static visible structures of thepatient's eye to maintain close alignment of the target site with themeasured optical and visual axes and the associated structural andphysical features of the patient's eye. Once the still image has beenproperly aligned either by a surgeon, a surgical team, at least one dataprocessor or a combination thereof, the surgeon can lock the image inplace.

In an optional fourth calibration step, the controlling surgeon places acalibration target having known dimensions and features into thereal-time multidimensional visualization of the target surgical fieldand triggers the apparatus to calibrate the target surgical field intoconsistent and useful measurable dimensions.

In a further step, the at least one data processor incorporates at leastone real-time, virtual reference indicium or multiple reference indiciaincluding data for making at least one limbal relaxing incision, cornealrelaxing incision, or a combination thereof into the real-timevisualization of the target surgical field. The virtual referenceindicia including data for making at least one limbal and/or cornealrelaxing incision can be highly patient specific. For example, in someembodiments, the indicia including data for making at least one limbaland/or corneal relaxing incision can include pre-determined shapes, suchas, but not limited to, arcs, lines, circles, ellipses, squares,rectangles, trapezoids, diamonds, triangles, polygons, and irregularvolumes including specific information pertaining to the incisions to bemade to correct the eye's astigmatism.

Although in the present exemplary embodiment, the virtual surgicalreference indicia including data for making at least one limbal and/orcorneal relaxing incision are incorporated into a real-timevisualization after alignment of the still image, in other embodiments,the virtual surgical reference indicia including data for making atleast one limbal and/or corneal relaxing incision are added as early asthe capturing of the pre-operative still image. It is within the scopeof the present description that the virtual surgical reference indiciaincluding data for making at least one limbal and/or corneal relaxingincision may be incorporated at any point up until the indicia areneeded during a surgical procedure. For example, the virtual surgicalreference indicia including data for making at least one limbal and/orcorneal relaxing incision can be added directly on the pre-operativestill image instantly after it is captured.

It is also within the scope of the present disclosure that a surgeon mayinput one or more freehand virtual surgical reference indicia on a stillimage or real-time multidimensional visualization Additionally, it isalso contemplated as being within the scope of the present descriptionto utilize pre-operative markings that are placed within the targetsurgical field on the patient so that the data processor will generatevirtual surgical reference indicia including data for making at leastone limbal and/or corneal relaxing incision according to the markingsfound on the pre-operative data set.

Further still, a surgeon may utilize multiple different virtual surgicalreference indicia including data for making at least one limbal and/orcorneal relaxing incision during a single surgical procedure or anysubpart thereof. For example, initial reference indicia including datafor making at least one limbal and/or corneal relaxing incision may bereplaced by other reference indicia including data for making at leastone limbal and/or corneal relaxing incision at any point during asurgery, or two or more different indicia may be used to represent morecomplex surgical markings.

Even further still, the at least one virtual reference indicia includingdata for making at least one limbal and/or corneal relaxing incision canbe tailored to a surgeons particular needs. Incision shapes, lengths andthicknesses are based on both inputted astigmatism data and algorithmsused by the surgeon to generate them. The astigmatism correctionalgorithm used by the surgeon can be tailored or can be replaced by anyappropriate re-calculated algorithm known in the art.

It should also be noted that when desired to correspond to a real-time3D HD visualization of the target surgical field, the real-time virtualsurgical reference indicia including data for making at least one limbaland/or corneal relaxing incision can be generated in 3D as well as inHD, or both, depending on the particular surgical procedure or upon theneeds of the surgeon. In some embodiments, either the real-time virtualreference indicia or data for making at least one limbal and/or cornealrelaxing incision can be in 3D and/or HD and vice versa. For example,and not intended to be a limitation, a 3D HD real-time virtual referenceindicia can be paired with 2D standard definition data for making atleast one limbal and/or corneal relaxing incision.

As described above in reference to FIG. 7 , once pre-operative patientdata still image 702 has been locked in place over real-time 3D HDvisualization 700 of the target surgical field, the apparatusincorporates at least one real-time, virtual surgical reference indiciaincluding data for making at least one limbal and/or corneal relaxingincision into the combined aligned pre-operative patient data stillimage 702 with real-time 3D HD visualization 700 of the patient's eye tofunction as a precise and rotationally accurate surgeon controlledreference indicia to facilitate the surgeon's making of at least oneappropriately sized, shaped and positioned limbal or corneal relaxingincision that will assist in producing superior post-surgical resultsand patient satisfaction.

It should be noted that it is within the scope and teachings of thepresent disclosure that the virtual surgical reference indicia includingdata for making at least one limbal and/or corneal relaxing incision canbe sized and modified according to the needs of the surgeon. Forexample, the indicium including data for making at least one limbalrelaxing incision can be sized, rotated and moved horizontally,vertically, and in depth as needed by the surgeon.

Further, the virtual surgical reference indicia including data formaking at least one limbal and/or corneal relaxing incision can becomposed of different types of indication markings and can be in HD. Forexample, without limitation, the markings can be monochromatic orcolored, with varying levels of transparency, composed of thin or thicklines, dashed or solid lines, a series of different shapes and the likeas is consistent with contemporary digital graphics technology. Further,the graphic presentation can be different within individual indicia tomore easily visualize the indicium in different areas or to emphasizespecific areas of interest.

Since the virtual reference indicia including data for making at leastone limbal and/or corneal relaxing incision described herein can trackthe vertical axis of a patient's eye, such indicia can be particularlyuseful for astigmatism correction procedures. Referring to FIG. 8 , eye800 is chemically dilated as evidenced by symmetrically dilated iris802. In one embodiment, indicium including data for making at least onelimbal relaxing incision 804 has a substantially circular shape. Itshould be noted that indicium including data for making at least onelimbal relaxing incision 804 can have any shape that may be useful foran astigmatism correcting procedure. Other shapes that can be usefulinclude, but are not limited to ellipses, squares, rectangles, diamonds,stars, trapezoids and the like. Combinations of shapes may also beuseful. Indicium including data for making at least one limbal relaxingincision 804 includes compass card 806. In one embodiment, compass card806 can include one or more graduated markings 808 for orientationreference. Graduated markings 808, can include information such as, butnot limited to, degree markings, limit information, minimum and maximumsettings, true patient axis markings and the like.

Further, indicium including data for making at least one limbal relaxingincision 804 includes accurate information about the patient's naturalvertical axis. For example, cross-hatch 810 can be used to track thenatural vertical axis of a patient's eye. Cross-hatch 810 includesvertical member 812 and can optionally include horizontal member 814. Itis most common for vertical member 812 to track the natural verticalaxis of a patient's eye. The identification means for tracking thevertical axis of the eye does not have to be of the form of cross-hatch810, but can be as simple as a straight solid line, a dashed line or thelike.

Indicium including data for making at least one limbal relaxing incision804 further includes one or more guides for making limbal relaxingincisions. In one embodiment illustrated in FIG. 8 , two guides can beused. Therein, first guide 816 and second guide 818 aid the surgeon inmaking rotationally accurate incisions in order to correct forastigmatism in the patient. First guide 816 and second guide 818 canoptionally include one or more arrow indicator 820 which further assiststhe surgeon in making an incision in an optimal direction. Indiciumincluding data for making at least one limbal relaxing incision 804 canfurther include first numeral 822 and second numeral 824 which can beused by a surgeon to make two or more incisions in a particular orderand can be any sequential numbering system, for example, whole numbers,Roman numerals, letters and the like. Even further still, first guide816 and second guide 818 can include a first and second guide line toindicate the beginning and end of an incision. If the cuts are to besymmetric, the lines are made of two lines intersecting at the center ofthe chemically dilated pupil. This ensures that the cuts will besymmetric.

In another exemplary embodiment, illustrated in FIG. 9 is an eye 900requiring four limbal relaxing incisions to correct astigmatism. Again,second indicium including data for making at least one limbal relaxingincision 902 includes compass card 904, graduated markings 906, andcross-hatch 908 for tracking the vertical axis. Second indiciumincluding data for making at least one limbal relaxing incision 902includes first guide 910, second guide 912, third guide 914 and fourthguide 916 all of which can include optional arrows and numerals forguiding a surgeon in the correct order of incision and direction of cut.Additionally illustrated in FIG. 9 is degree designation 918 wherein thetotal degree distance of a cut is indicated. These features can beinserted into any indicium described herein at the discretion of thesurgeon Again, in FIG. 9 , all four guides are flanked by cross-hatchlines to indicate the beginning and end of the cut and the linesintersect at the center of the pupil to ensure symmetry of the limbalrelaxing incisions.

In still another exemplary embodiment, illustrated in FIG. 10 is eye1000 requiring four limbal relaxing incisions to correct astigmatism.Again, third indicium including data for making at least one limbalrelaxing incision 1002 includes compass card 1004, graduated markings1006, and cross-hatch 1008 for tracking the vertical axis Third indiciumincluding data for making at least one limbal relaxing incision 1002includes first guide 1010, second guide 1012, third guide 1014 andfourth guide 1016 all of which can include optional arrows and numeralsfor guiding a surgeon in the correct order of incision and direction ofcut in third indicium including data for making at least one limbalrelaxing incision 1002, first guide 1010 and third guide 1014 are backto back as are second guide 1012 and fourth guide 1016. Additionallythird indicium including data for making at least one limbal relaxingincision 1002 includes guides that do not begin at the vertical axis,but rather are displaced by variable angle 1018. These features can beinserted into any indicium described herein at the discretion of thesurgeon Again, in FIG. 10 , all four guides are flanked by cross-hatchlines to indicate the beginning and end of the cut and the linesintersect at the center of the pupil to ensure symmetry of the limbalrelaxing incisions.

FIG. 11 illustrates an embodiment wherein a laser is used to incisespots into regions of the limbus or even in the cornea to correctastigmatism. Eye 1100 requires six limbal relaxing incisions and onecorneal relaxing incision in the form of laser spots to correctastigmatism. Again, forth indicium including data for making at leastone limbal and corneal relaxing incision 1102 includes compass card1104, graduated markings 1106, and cross-hatch 1108 for tracking thevertical axis. Forth indicium including data for making at least onelimbal and corneal relaxing incision 1102 includes first limbal guidespot 1110, second limbal guide spot 1112, third limbal guide spot 1114,fourth limbal guide spot 1116, fifth limbal guide spot 1118, sixthlimbal guide spot 1120 and seventh corneal guide spot 1122 all of whichcan include numerals for guiding a surgeon in the correct order ofincision. Guide spots do not need to be symmetrical and can be placedinto a template before the indicium is aligned and then subsequentlyaligned with the vertical axis of the eye.

In yet another exemplary embodiment, illustrated in FIG. 12 is eye 1200requiring two limbal relaxing incisions and one corneal relaxingincision to correct for astigmatism. Again, fifth indicium includingdata for making at least one limbal and/or corneal relaxing incision1202 includes compass card 1204, graduated markings 1206, andcross-hatch 1208 for tracking the vertical axis. Third indiciumincluding data for making at least one limbal and/or corneal relaxingincision 1202 includes first corneal guide 1210, second limbal guide1212 and third limbal guide 1214 all of which can include optionalarrows and numerals for guiding a surgeon in the correct order ofincision and direction of cut. In fifth indicium including data formaking at least one limbal and/or corneal relaxing incision 1202, firstcorneal guide 1210, second limbal guide 1212 and third limbal guide 1214are randomly located based on a surgeons recommendation. Additionallyfifth indicium including data for making at least one limbal and/orcorneal relaxing incision 1202 includes guides that do not begin or endat the vertical axis, but rather are displaced by variable angle 1216.These features can be inserted into any indicium described herein at thediscretion of the surgeon.

Typically, once at least one rotationally accurate indicium includingdata for making at least one limbal and/or corneal relaxing incision hasbeen added to a real-time visualization of the target surgical field andis properly aligned with the vertical axis, a surgeon can make theproper limbal and/or corneal relaxing incisions to correct forastigmatism.

A surgeon will find that the apparatus and methods disclosed hereinprovide many advantages over existing technology. Firstly, as ocularsurgeons are aware, incision markings commonly associated with limbaland/or corneal relaxing incisions to correct astigmatism are hard toestimate with the naked eye, and even if markings are made on the eyeitself, those markings are not commonly effective once a procedure hascommenced. The present disclosure provides apparatus and methods whichassist a surgeon in aligning with rotational accuracy at least onelimbal and/or corneal relaxing incision with the vertical axis of an eyeby providing easy to see real-time virtual indicia including data formaking at least one limbal and/or corneal relaxing incision.

Further, the reference indicium or indicia including data for making atleast one limbal and/or corneal relaxing incision are not affected bythe surgical procedure itself. Therefore, they remain as constantreferences even when the target tissues are subjected to fluids andwiping. More importantly, the indicia including data for making at leastone limbal and/or corneal relaxing incision are precise, rotationallyaccurate and tissue and structure specific, rather than theapproximations known in the art. Further, the indicium can be changed,removed, and reinstated as needed to provide an added degree of controland flexibility to the performance of a surgical procedure. For example,a controlling surgeon can chose to vary the transparency or remove areference indicium including data for making at least one limbalrelaxing incision altogether from a visualization to give a more clearview of underlying tissues or structural features and then reinstate theindicium to function as a template or guide for astigmatism correction.

Unless otherwise indicated, all numbers expressing quantities ofingredients, properties such as molecular weight, reaction conditions,and so forth used in the specification and claims are to be understoodas being modified in all instances by the term “about.” Accordingly,unless indicated to the contrary, the numerical parameters set forth inthe specification and attached claims are approximations that may varydepending upon the desired properties sought to be obtained by thepresent invention. At the very least, and not as an attempt to limit theapplication of the doctrine of equivalents to the scope of the claims,each numerical parameter should at least be construed in light of thenumber of reported significant digits and by applying ordinary roundingtechniques. Notwithstanding that the numerical ranges and parameterssetting forth the broad scope of the invention are approximations, thenumerical values set forth in the specific examples are reported asprecisely as possible. Any numerical value, however, inherently containscertain errors necessarily resulting from the standard deviation foundin their respective testing measurements.

The terms “a,” “an,” “the” and similar referents used in the context ofdescribing the invention (especially in the context of the followingclaims) are to be construed to cover both the singular and the plural,unless otherwise indicated herein or clearly contradicted by context.Recitation of ranges of values herein is merely intended to serve as ashorthand method of referring individually to each separate valuefalling within the range. Unless otherwise indicated herein, eachindividual value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g., “such as”) provided herein isintended merely to better illuminate the invention and does not pose alimitation on the scope of the invention otherwise claimed No languagein the specification should be construed as indicating any non-claimedelement essential to the practice of the invention.

Groupings of alternative elements or embodiments of the inventiondisclosed herein are not to be construed as limitations Each groupmember may be referred to and claimed individually or in any combinationwith other members of the group or other elements found herein. It isanticipated that one or more members of a group may be included in, ordeleted from, a group for reasons of convenience and/or patentability.When any such inclusion or deletion occurs, the specification is deemedto contain the group as modified thus fulfilling the written descriptionof all Markush groups used in the appended claims.

Certain embodiments of this invention are described herein, includingthe best mode known to the inventors for carrying out the invention. Ofcourse, variations on these described embodiments will become apparentto those of ordinary skill in the art upon reading the foregoingdescription. The inventor expects skilled artisans to employ suchvariations as appropriate, and the inventors intend for the invention tobe practiced otherwise than specifically described herein. Accordingly,this invention includes all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the invention unlessotherwise indicated herein or otherwise clearly contradicted by context.

Furthermore, numerous references have been made to patents and printedpublications. Each of the above-cited references is individuallyincorporated herein by reference in their entirety.

Specific embodiments disclosed herein may be further limited in theclaims using consisting of or and consisting essentially of language.When used in the claims, whether as filed or added per amendment, thetransition term “consisting of” excludes any element, step, oringredient not specified in the claims. The transition term “consistingessentially of” limits the scope of a claim to the specified materialsor steps and those that do not materially affect the basic and novelcharacteristic(s). Embodiments of the invention so claimed areinherently or expressly described and enabled herein.

In closing, it is to be understood that the embodiments of the inventiondisclosed herein are illustrative of the principles of the presentinvention. Other modifications that may be employed are within the scopeof the invention. Thus, by way of example, but not of limitation,alternative configurations of the present invention may be utilized inaccordance with the teachings herein. Accordingly, the present inventionis not limited to that precisely as shown and described.

What is claimed is:
 1. A method for guiding an astigmatism correctionprocedure on an eye of a patient, the method comprising: receiving, froma first photosensor, a pre-operative still image of an ocular targetsurgical site of the patient prior to the astigmatism correctionprocedure; producing a virtual indicium that includes data for guidingthe astigmatism correction procedure in conjunction with thepre-operative still image such that the virtual indicium is rotationallyaccurate with respect to the ocular target surgical site displayedwithin the pre-operative still image; receiving from a real-time,multidimensional visualization module a real-time multidimensionalvisualization of the ocular target surgical site during the astigmatismcorrection procedure; aligning the pre-operative still image includingthe rotationally accurate virtual indicium with the multidimensionalvisualization; and displaying the multidimensional visualization of theocular target surgical site in conjunction with the rotationallyaccurate virtual indicium.
 2. The method according to claim 1, furthercomprising: obtaining the pre-operative still image of the patient priorto cyclorotation of the eye when the patient lies down for surgery. 3.The method according to claim 1, wherein aligning the pre-operativestill image with the multidimensional visualization includes:determining a specific visual feature within the ocular target surgicalsite within the pre-operative still image; identifying the specificvisual feature within the multidimensional visualization; and rotating,moving, and positioning the pre-operative still image such that thespecific visual feature of the pre-operative still image is overlaid ontop of the specific visual feature of the ocular target surgical siteincluded within the multidimensional visualization.
 4. The methodaccording to claim 3, further comprising: including in the specificvisible feature at least one of a vasculature, a vascular network, avascular branching pattern, a pattern in an iris, a scratch on a cornea,a dimple on the cornea, a retinal feature, a limbus, a pupillaryboundary, a deformity, a void, a blotch, a sequestered pigment cell, ascar, an intentionally placed marking, and a dark region.
 5. The methodaccording to claim 1, further comprising: incorporating information inthe virtual indicium for making at least one limbal relaxing incision,at least one corneal relaxing incision, at least one astigmatickeratotomy incision, or a combination thereof, and wherein theastigmatism correction procedure includes at least one of a limbalrelaxing incision, a corneal relaxing incision, an astigmatic keratotomyincision and an intra-ocular lens implantation incision.
 6. The methodaccording to claim 1, further comprising: causing at least one of themultidimensional visualization, the pre-operative still image, and thevirtual indicium to be stereoscopic.
 7. The method according to claim 1,further comprising: displaying the virtual indicium in conjunction withthe multidimensional visualization after detecting that thepre-operative still image is locked into place with the multidimensionalvisualization.
 8. An apparatus for guiding an astigmatism correctionprocedure on an eye of a patient, the apparatus comprising: a dataprocessor configured to: receive, from a first photosensor, apre-operative still image of an ocular target surgical site of thepatient prior to the astigmatism correction procedure; produce a virtualindicium that includes data for guiding the astigmatism correctionprocedure in conjunction with the pre-operative still image such thatthe virtual indicium is rotationally accurate with respect to the oculartarget surgical site displayed within the pre-operative still image;receive from a real-time, multidimensional visualization module areal-time multidimensional visualization of the ocular target surgicalsite during the astigmatism correction procedure; align thepre-operative still image including the rotationally accurate virtualindicium with the multidimensional visualization; and display themultidimensional visualization of the ocular target surgical site inconjunction with the rotationally accurate virtual indicium.
 9. Theapparatus according to claim 8, further comprising: a control interfaceoperating in conjunction with the data processor, the control interfacebeing configured to: display the pre-operative still image within acomputer display; receive the virtual indicium provided by a surgeonwith respect to a position of tissue within the ocular target surgicalsite displayed by the pre-operative still image; and cause the dataprocessor to integrate the virtual indicium with the pre-operative stillimage such that the virtual indicium is displayed in a selected positionwith respect to adjacent tissue.
 10. The apparatus according to claim 8,wherein: the data processor is configured to cause at least one of themultidimensional visualization, the pre-operative still image, and thevirtual indicium to be stereoscopic.
 11. The apparatus according toclaim 8, wherein: the virtual indicium includes a graphicalrepresentation of at least one of a) a size of components of the eye, b)a shape of components of the eye, c) an optical characteristic of theeye, d) a magnitude of astigmatism of the eye, e) a direction of theastigmatism of the eye, f) an angular gradation marking, g) across-hatch marking showing a vertical axis of the eye, h) a visual axisof the eye, i) a diameter of a limbus of the eye, j) a diameter of apupil of the eye, k) a residual astigmatism of the eye, l) a steepmeridian of the astigmatism of the eye, m) a flat meridian of theastigmatism of the eye, n) a gradation from the vertical axis of theeye, o) a gradation from a horizontal axis of the eye, p) a direction ofan incision, and q) an order of at least two incisions.
 12. Theapparatus according to claim 8, wherein aligning the pre-operative stillimage with the multidimensional visualization includes: determining aspecific visual feature within the ocular target surgical site withinthe pre-operative still image; identifying the specific visual featurewithin the multidimensional visualization; and rotating, moving, andpositioning the pre-operative still image such that the specific visualfeature of the pre-operative still image is overlaid on top of thespecific visual feature of the ocular target surgical site includedwithin the multidimensional visualization.
 13. The apparatus accordingto claim 12, wherein: the specific visible feature includes at least oneof a vasculature, a vascular network, a vascular branching pattern, apattern in an iris, a scratch on a cornea, a dimple on the cornea, aretinal feature, a limbus, a pupillary boundary, a deformity, a void, ablotch, a sequestered pigment cell, a scar, an intentionally placedmarking, and a dark region.
 14. The apparatus according to claim 12,wherein: the specific visible feature is determined as being static withrespect to other features within the ocular target surgical site.
 15. Acomputer readable medium storing a set of computer instructions forguiding an astigmatism correction procedure on an eye of a patient, theset of computer instructions being executable by a processor andcomprising: receiving, from a first photosensor, a pre-operative stillimage of an ocular target surgical site of the patient prior to theastigmatism correction procedure; producing a virtual indicium thatincludes data for guiding the astigmatism correction procedure inconjunction with the pre-operative still image such that the virtualindicium is rotationally accurate with respect to the ocular targetsurgical site displayed within the pre-operative still image; receivingfrom a real-time, multidimensional visualization module a real-timemultidimensional visualization of the ocular target surgical site duringthe astigmatism correction procedure; aligning the pre-operative stillimage including the rotationally accurate virtual indicium with themultidimensional visualization; and displaying the multidimensionalvisualization of the ocular target surgical site in conjunction with therotationally accurate virtual indicium.
 16. The computer readable mediumaccording to claim 15, further comprising: obtaining the pre-operativestill image of the patient prior to cyclorotation of the eye when thepatient lies down for surgery.
 17. The computer readable mediumaccording to claim 15, wherein the virtual indicium includes a graphicalrepresentation of at least one of a) a size of components of the eye, b)a shape of components of the eye, c) an optical characteristic of theeye, d) a magnitude of an astigmatism of the eye, e) a direction of theastigmatism of the eye, f) an angular gradation marking, g) across-hatch marking showing a vertical axis of the eye, h) a visual axisof the eye, i) a diameter of a limbus of the eye, j) a diameter of apupil of the eye, k) a residual astigmatism of the eye, l) a steepmeridian of the astigmatism of the eye, m) a flat meridian of theastigmatism of the eye, n) a gradation from the vertical axis of theeye, o) a gradation from a horizontal axis of the eye, p) a direction ofan incision, and q) an order of at least two incisions.
 18. The computerreadable medium according to claim 15, wherein aligning thepre-operative still image with the multidimensional visualizationincludes: determining a specific visual feature within the ocular targetsurgical site within the pre-operative still image; identifying thespecific visual feature within the multidimensional visualization; androtating, moving, and positioning the pre-operative still image suchthat the specific visual feature of the pre-operative still image isoverlaid on top of the specific visual feature of the ocular targetsurgical site included within the multidimensional visualization. 19.The computer readable medium according to claim 18, wherein the specificvisible feature includes at least one of a vasculature, a vascularnetwork, a vascular branching pattern, a pattern in an iris, a scratchon a cornea, a dimple on the cornea, a retinal feature, a limbus, apupillary boundary, a deformity, a void, a blotch, a sequestered pigmentcell, a scar, an intentionally placed marking, and a dark region.